In the field of dental care, replacement teeth are typically retained in place by means of bridge work or the like extending from the replacement tooth and anchored to adjacent healthy teeth. The manufacture of such replacement teeth and their mechanical bridge structure requires careful work to insure proper fitting thereof with respect to adjacent teeth. Also, restoration procedures such as the capping of decayed or broken teeth likewise requires close attention to the precise positions of proximate teeth.
To accurately form and position the replacement tooth or cap, a dentist usually makes a dental negative or impression of the relevant tooth or gap, typically including at least the adjacent teeth. This impression may be partial, unilateral or bilateral, depending upon the extent of the work to be done, and serves as a mold for eventually developing, e.g., a die of the patient's tooth to be replaced or restored. For example, when a tooth is to be crowned or otherwise rebuilt, it is conventional to make a negative casting or impression of the tooth using a rubber-like impression material, the impression then being used as a mold for preparing a positive replica of the tooth to be restored. The replica is then used to assist in forming a crown model of the tooth which, in turn, provides a form or die for making the crown. If needed, a full-bite positive replica of the teeth will be prepared for use in ensuring that the upper and lower teeth sets will close together properly.